ES2757774T3 - Coagulation monitoring device, coagulation monitoring procedure and coagulation system - Google Patents

Abstract

A coagulation monitoring device (2) for monitoring a treatment status of the water to be treated (8) undergoing a coagulation treatment, comprising: a laser light irradiation part (10) configured to irradiate laser light in a measurement area (18) of the water to be treated, such that the laser light is emitted at least at predetermined time intervals and subjected to amplitude modulation at a predetermined frequency; a scattered light receiving part (12) configured to receive scattered light from particles of the water to be treated that are in the measurement zone; a signal processing part (36) configured to extract a measurement value indicative of a scattered light intensity, from the light receiving signal obtained at the scattered light receiving part; and a measurement value calculation piece configured to continuously or discontinuously capture m plural measurement value sets, each set consisting of n measurement values where m = 2 or more and n = 2 or more; characterized in that the measurement value calculation piece is configured to extract a plurality of measurement values in ascending order from a lower value for each set, the measurement value calculation piece is configured to determine an average measurement value from a plurality of extracted measurement values with the lowest value removed therefrom.

Description

D E S C R IP C IÓ N

Coagulation monitoring device, coagulation monitoring procedure and coagulation system

TECHNICAL FIELD

The present invention relates to a monitoring technique in a coagulation treatment of the water to be treated such as, for example, clean water, industrial water and wastewater, and to a technique of using the same.

TECHNICAL BACKGROUND

In the coagulation treatment of the water to be treated such as clean water, industrial water and wastewater, a solid-liquid separation such as precipitation separation, pressure float separation, centrifugal separation, sand filtration is carried out. and membrane separation, for example, after the coagulation treatment of a suspended solid (SS) in the water to be treated using an inorganic coagulant or an organic coagulant. The SS coagulation state fluctuates depending on pH, coagulant dose, agitation conditions, etc., which can lead to deterioration of the water quality of the water to be treated and adversely affect the solid separation treatment - liquid in the later stage if the coagulation treatment is not carried out under appropriate conditions.

Such a coagulation treatment may employ a procedure to establish coagulation conditions in laboratory tests. However, if it takes a long time to establish the coagulation conditions in the actual coagulation treatment, the water quality of the water to be treated may fluctuate, making it difficult to accurately capture the SS coagulation state. Therefore, in order to establish the optimal coagulation conditions, such as pH, coagulant dosage and agitation conditions, it is important to monitor in real time the status of the treatment of the water to be treated during the treatment of coagulation so that the SS coagulation status is monitored.

In connection with this monitoring of coagulation, it is known: to apply laser light to the water to be treated, to receive light scattered by particles in the water to be treated; subjecting the received light signal to an amplitude modulation (AM) detection; and thereafter finding the lowest value of signal intensity to determine the coagulant dose from the lowest value (eg, patent document 1). In this coagulation monitoring, the lowest signal strength value of the scattered light is found, so that the light scattered by the non-coagulated suspended solids is detected so that it can be distinguished from the light scattered by the coagulated substances in the water to be treated.

With respect to laser light for use in this coagulation monitoring, it is known to use laser light which is emitted at predetermined time intervals by intermittent activation of a laser diode (eg patent document 2). This emission mode that reduces the emission time extends the availability time of the laser light emitting element.

DOCUMENTS OF THE PREVIOUS TECHNIQUE PATENT DOCUMENTS

Patent Document 1: Japanese Patent Publication Open for Public Consultation No. 2002-195947.

Patent Document 2: Japanese Patent Publication Open for Public Consultation No. 2005-241338.

The prior art can be found for example in JP 2007271333 A which discloses a procedure for monitoring the effect of the papermaking agent and the injection quantity control procedure in US 2014/0131259 A1 which discloses a system and procedures for determining the turbidity of the liquid phase of multi-phase wastewater and in JP 2004 170298 A that reveals a probe and a detector for detecting the condition of the particles.

SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

Incidentally, the coagulation treatment of the water to be treated uses a dosing system that measures the concentration of unincorporated SS in the floc generated so that the dosage of the coagulant is controlled on the basis of the measurement value. In SS concentration measurement, laser light is applied to a measurement area of the water to be treated, and scattered light is received from the measurement area to obtain a Measurement value indicative of SS concentration from a signal level acquired through scattered light photoelectric conversion.

This dosing system evaluates the coagulation state by defining an upper limit for dosing and maintaining the lower value for a certain period of the signal level described above. Since this procedure defines the upper limit for the amount of SS or the dosage, stable measurement is feasible if the amount of floc formed is removed.

However, some of the water to be treated may require a large amount of coagulant and therefore a large amount of floc may form. In this case, the floc increases in the amount of generation and grows, which acts to decrease the timing of the measurement of the amount of SS between the flocs. For this reason, the lowest measurement value is maintained for a certain period of time, while the lowest measurement value of the water to be treated is updated at regular time intervals so that the dose is determined using this lower value as the amount of SS left between blocks.

In the case of maintaining the lowest measurement value and updating the lowest value at regular time intervals in this way, an increased amount of floc generated needs to extend the measurement value holding time. The holding time of the extended measurement value reduces the effect of shortening the delay time in the control system, which is compensated by measuring the water to be treated in the treatment in a coagulation tank. Assuming typical proportional integral derivative (PID) control, the dosing control based on the lowest measurement value needs to use a measurement value correlated with the SS remaining between the flocs, as the measurement value for dosing control. Although the lowest measurement value needs to be updated at regular intervals of time if the turbidity measurement opportunity decreases due to the increase in the amount of floc and SS between flocs, the extension of the time interval to update the value of the In a non-advantageous way, the dosing system may lose the control delay compensation behavior.

Regarding the measurement value holding time, theoretically it may be possible to sequentially adjust the measurement value holding time depending on the situations of the water treatment to be treated, in order to optimize the maintenance time. However, in a coagulation treatment in, for example, a food manufacturing plant where drainage species are changed in a short period of time, there is a problem that monitoring the status of the treatment may involve difficulty.

In the case of using a laser diode as a laser light-emitting element, a long-term use is difficult since its emission life is as short as several thousand hours. Therefore, the use of laser light emitted at regular intervals of time can be effective as life-prolonging measures for the laser light emitting element. However, limiting the emission time and timing of light emission causes the problem that the time to measure the amount of SS between flocs is affected if the amount of flocs is large, making accurate measurement difficult .

Patent documents 1 and 2 do not disclose or suggest such requirements or problems or configurations, etc. to resolve them.

Therefore, in view of the above problems, an object of the present invention is to provide a coagulation monitoring device or a coagulation monitoring method, capable of stably measuring the turbidity of uncoagulated SS water which it will be treated, without being affected by flocs even if they are formed in large quantities.

Another object of the present invention is to implant a coagulation system that guarantees a reliable coagulation treatment while maintaining the compensation behavior in a dosage control without being affected by flocs, through the use of the device for monitoring the coagulation or the coagulation monitoring procedure.

MEANS TO SOLVE THE PROBLEM

In order to achieve the above objects, a coagulation monitoring device of the present invention is defined by the respective claims.

In order to achieve the above objects, a coagulation monitoring method of the present invention is defined by the respective claims.

In order to achieve the above objects, a coagulation system of the present invention is defined by the respective claims.

EFFECT OF THE INVENTION

In accordance with the present invention, any of the following effects can be obtained. <Coagulation monitoring device or coagulation monitoring procedure>

(1) Although a large number of flocs are produced in the water to be treated during coagulation with an increased floc density, the influences induced by the flocs can be avoided so that the SS turbidity of the water that to be treated can be measured stably.

(2) The influence of the flocs on weak scattered light and the influence of light protection by the flocs can be alleviated or avoided so that the status of the treatment of the water to be treated during coagulation can be captured accurately in real time and in a short measurement time. This allows the dosage of the coagulant to be selected depending on the state of the treatment.

<Coagulation system>

(1) The treatment status of the water to be treated during the coagulation treatment can be captured in real time through a stable measurement of the SS turbidity of the water to be treated, based on the conditions of coagulation of the water to be treated and the dosage of the coagulant can be determined.

(2) Coagulation performance can be improved through optimization of the dosage for the water to be treated and through stable coagulation treatment.

Other objects, features and advantages of the present invention will become better apparent with reference to the accompanying drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a block diagram showing an example of a coagulation monitoring device according to a first embodiment.

Fig. 2 is a block diagram showing an example of a lower value detection circuit. Fig. 3 is a view showing an example of operating waveforms.

Fig. 4 is a view showing tables of measurement values and calculation of the average measurement value. Figure 5 is a flowchart showing a coagulation monitoring procedure.

Fig. 6 is a view showing an example of a coagulation system according to a second embodiment.

Figure 7 is a view showing an example of a coagulant calculation table.

Fig. 8 is a flow chart showing a process of a coagulation treatment.

WAYS TO CARRY OUT THE INVENTION

[First embodiment]

Figure 1 shows a coagulation monitoring device according to a first embodiment. The configuration shown in Figure 1 is merely an example and is not intended to limit the coagulation monitoring device, the coagulation monitoring method, or the coagulation system of the present invention.

A coagulation monitoring device 2 includes a sensor part 4. By way of example, the sensor part 4 is kept in a state immersed in the water 8 to be treated within a coagulation tank 6. The part of the Sensor 4 includes a laser light irradiation part 10 and a scattered light receiving part 12. The laser light irradiation part 10 is formed at a light output end of a first optical fiber 14-1 which guides the laser light. The scattered light receiving part 12 is formed at a light input end of a second optical fiber 14-2 that guides the scattered light.

A protection element 16 is interposed between the laser light irradiation part 10 and the scattered light receiving part 12 so as to define a measurement area 18. The measurement area 18 is irradiated by the laser light from the irradiation piece of laser light 10, emitted from a laser light emitting piece 20. The area of Measurement 18 is an example of a laser irradiated area in the water to be treated 8. When irradiated in Measurement Area 18, the laser light is scattered due to particles in the water to be treated 8 , generating scattered light. The scattered light receiving part 12 receives this scattered light from the measurement area 18. In this case, if there are flocs in the measurement area 18, the flocs affect the scattered light.

The protection element 16 acts not only as a means of fixing and supporting the optical fibers 14-1 and 14-2, but also as a means of protection from natural light for the measurement area 18. The protection element 16 includes, as an example, a corner angled part 24 having a certain defined angle between a first support part 22-1 that fixes and supports the optical fiber 14-1 and a second support part 22-2 that supports the fiber optics 14 -2. The angle of the angled part at vertex 24 is preferably 90 degrees, for example, but can be any other angle. The corner angled part 24 faces measurement area 18 and intervenes between the laser light irradiation part 10 and the scattered light receiving part 12. This can prevent the laser light from the irradiation part The laser light 10 enters the scattered light receiving part 12, allowing the scattered light receiving part 12 to receive scattered light towards particles in the measurement zone 18.

The laser light emitting part 20 includes a laser emitting element 26 and a light emitting circuit 28. The laser emitting element 26 is an example of a laser light source that emits laser light. The laser light source is preferably a laser diode, but it can be any element or device from which laser light can be obtained. For example, a light emitting diode can be used.

Light emitting circuit 28 is an example of means for activating laser emitting element 26. Light emitting circuit 28 includes, by way of example, an amplitude modulation (AM) modulator circuit 30, a timer circuit 32 and a function generator 34. The AM modulator circuit 30 subjects a timing signal Ts to an amplitude modulation (AM modulation) using a modulation signal Ms with a predetermined frequency f, to output an output signal. Dr emission having a predetermined frequency amplitude fe flashes at predetermined time intervals. On receiving the emission signal Dr, the laser emitter element 26 varies with the modulation signal Ms and repeats emission and non-emission at predetermined time intervals based on the timing signal Ts. This reduces the emission time of the laser emitting element 26 for monitoring coagulation. In the case of using the laser diode as laser emitting element 26, the laser diode can be prevented from deteriorating due to continuous illumination, while extending the available time regardless of its emission lifetime as short as several thousand hours.

Timing circuit 32 generates timing signal Ts. The timing signal Ts can be, for example, an intermittent pulse signal in a given cycle. The timing signal Ts is used as timing information for processing the lowest average value calculation.

Function generator 34 is an example of an oscillator that oscillates the modulation signal Ms. The modulation signal Ms is preferably of a frequency f capable of circumventing the influence of natural light on laser light, and the frequency may be of , for example, f = 70 to 150 [kHz]. The shape of the signal can be a periodic signal with the same amplitude and the shape of the wave can be any of a sine wave, triangle wave, square wave etc.

When the laser light obtained from said laser light emitting part 20 is radiated onto the measurement zone 18, the scattered light, which has been scattered by fine colloidal particles existing in this measurement zone 18 enters the part of reception of scattered light 12. In this case, the fine colloidal particles are non-coagulated colloidal particles. The scattered light obtained by the fine colloidal particles has a frequency similar to that of the laser light radiated from the laser light irradiation piece 10 and is intermittent in shape at a given cycle.

A light receiving output from the scattered light receiving part 12 is routed through the optical fiber 14-2 to a signal processing part 36. The signal processing part 36 performs a photoelectric conversion, it eliminates noise components and acquires a level signal indicative of the intensity of the scattered light and a representative measurement value of the intensity of the scattered light from the level signal. Signal processing part 36 includes, by way of example, a photoelectric conversion circuit 38 and a detector circuit 40.

The photoelectric conversion circuit 38 includes a photo detector 42, a bandpass filter 44 and an amplifier 46. The photo detector 42 receives scattered light conducted through the optical fiber 14-2, for conversion into an electrical signal Ei . The bandpass filter 44 cuts the noise components of the electrical signal Ei to extract a signal component from the modulation signal Ms.. By setting a cutoff frequency of the bandpass filter 44, unnecessary jitter components are removed from so that a component of the modulation signal Ms is output. Amplifier 46 amplifies the signal component of the modulation signal Ms in the scattered light, to output a light receiving signal Eo having an amplitude level depending on of scattered light. In this photoelectric conversion circuit 38, the photo detector 42 can be replaced by a photodiode, and the bandpass filter 44 can be replaced by a lowpass filter.

Detector circuit 40 detects an output signal Do from the light receiving signal Eo by AM detection (envelope detection). The output signal Do indicates a DC component level of the light receiving signal Eo. This level represents a level of scattered light that appears from particles in the water to be treated that contains fine colloidal particles. This contains reflection components from noise components and flocs that are scattered light from other substances in addition to the fine colloidal particles.

An output from the detector circuit 40 is fed to a lower value detection circuit 48. The lower value detection circuit 48 is an example of a measurement value calculation part. The lower value detection circuit 48 finds a measurement value d indicative of turbidity SS from a level (signal intensity) of the output signal Do, to determine a lower measurement value of the scattered light by calculation processing. Lower value detection circuit 48 performs processing, such as analog to digital (A / D) conversion of the output signal Do, comparison of measurement values, recording of measurement values and from the calculation of an average measurement value dav.

<Lower value detection circuit 48>

The lower value detection circuit 48 is implemented by for example a circuit including a computer such as a microprocessor, as shown in Fig. 2. The lower value detection circuit 48 includes an analog-to-digital converter ( A / D) 50, a processor 52 and a memory piece 54. The A / D converter 50 converts the output signal Do into a measurement value d which is a digital signal.

Processor 52 is an example of a calculation circuit that operates an average measurement value of the measurement values. Processor 52 runs an operating system (OS) and a coagulation program present in memory piece 54, thereby performing the calculation, such as comparing measurement values, recording measurement values, and calculation of an average measurement value (lowest measurement value).

The memory part 54 is an example of a recording part and includes a program storage part 56, a data recording part 58 and a random access memory (RAM) 60. The program storage part 56 stores programs such as the operating system and coagulation program described earlier in this document. Data recording part 58 stores a plurality of tables of measurement values for use in calculating the average measurement value. RAM 60 is used as a work area for information processing.

A result of the computation of the processor 52 is output from the processor 52 to a display piece 62. For example, a liquid crystal display (LCD) is used as the display piece 62. The display piece 62 displays various data, such as the measurement values used in the calculation of the processor 52 and a lower measurement value that is the result of the calculation.

<Principle of measurement in coagulation treatment>

The coagulant is dosed and stirred into the water 8 to be treated within the coagulation reservoir 6 to promote coagulation treatment. When this agitation causes the fine colloidal particles to move to measurement zone 18, the light scattered from the fine colloidal particles fluctuates. The cycle of this fluctuation can be assumed and estimated from the number of collisions in measurement area 18 considered as particles with fine colloidal particles. If the measurement zone 18 and the fine colloidal particles are approximated by spheres with radii R and r, respectively, a collision cross section Qo can be expressed as

Qo = n (R r) 2 (1)

As follows from this equation, the collision cross section Qo is proportional to the square of the sum of the radii R and r.

Assuming an area of the cross section perpendicular to a flow of particles with an average radius r at a density of colloidal particles N [pieces / m3] passing through the measurement zone 18 with a radius R from a certain direction at an average speed v [m / s], the number of times v by which a fine colloidal particle enters measurement zone 18 per unit time can be expressed as

v = NQov (2)

Also when the fine colloidal particle leaves the measurement zone 18, a similar fluctuation occurs and the cycle of the differential value of the intensity of the scattered light is equal to twice the number of times v. Assuming that the intensity of the scattered light is proportional to the nth power of the particle radius of a fine colloidal particle, a fluctuation A of the intensity of the scattered light accompanying a movement of a fine colloidal particle is expressed as

A = Aorn (3)

if multiple dispersion is ignored. Ao is a constant that depends on the measurement system and is a value calibrated using a standard sample.

Since fine colloidal particles before coagulation have a small radius r and a high particle density N, negligible fluctuations of scattered light occur in a short cycle.

Therefore, by detecting a component of the modulation frequency through the detector circuit 40, its output waveform can perform equivalent signal processing to pass through the bandpass filter 44 or the lowpass filter. That is, the proper selection of the cutoff frequency of the bandpass filter 44 allows detection of an output signal Do from which a jitter component is removed due to this modulation frequency component.

Incidentally, the colloid (coagulated colloid) coagulated from the water to be treated 8 experiences large fluctuations as it enters and leaves measurement zone 18 and has an elongated average fluctuation cycle. If the product of the density of the coagulated colloid and the volume of the measurement zone 18 is less than 1, the lowest value of the output waveform after detection of the detector circuit 40 corresponds to the dispersion of the colloid no. coagulated.

Although the output signal Do obtained by the detector circuit 40 contains a signal from the scattered light from the uncoagulated colloid and a signal from the other scattered light, the scattered light from the coagulated colloid in the water to be treated 8 is It can distinguish from scattered light from uncoagulated colloid by the level of signal amplitude. Accordingly, by extracting a signal component of an amplitude level corresponding to the scattered light of the uncoagulated colloid from this output signal Do, the coagulation state of the colloid can be detected and captured as the treatment state. of the water to be treated 8.

<Signal Processing and Measurement Value Signal Processing>

Figure 3 shows the signal processing that extracts a value from the SS turbidity measurement of the scattered light. This signal processing includes capture processing of a set m (m = 2 or more) of measurement values, each set consisting of n consecutive or non-consecutive n measurement values (eg, n = 2 or more), in order to calculate an average measurement value from a plurality of measurement values.

This signal processing involves capturing two sets SI and SII of measurement values with 1 set = 8 measurement values d. For the convenience of the description, the SI set contains values of the measurement d11, d12, d13 ..., while the SII set contains values of the measurement d21, d22, d23 ...

In this signal processing, a timing signal Ts is a pulse signal that has a certain pulse width tw in a certain time interval T (cycle), as shown in A of Figure 3. In this case, the level segment H (= pulse width tw) is a time of emission of laser light, while the level segment L (= T-tw) is a time of no emission of laser light. By way of example, T = 2 [sec] and tw = 0.2 [sec] are established. In this case, you can set T-tw = 2 [sec].

The modulation signal Ms is a periodic signal with a certain frequency f and the same amplitude, as shown in B in figure 3. The frequency f can be selected from the range of 70 to 150 [kHz].

The emission signal Dr is an output signal from the modulator circuit AM 30 that modulates the timing signal Ts with the modulation signal Ms, as shown in C of Figure 3. In other words, the emission signal Dr is a periodic signal which is superimposed on the modulation signal Ms in the pulse width tw of the level segment H of the timing signal Ts. That is, the emission signal Dr is a periodic signal whose pulse width tw varies according to the amplitude of the modulation signal Ms and which flashes using the timing signal Ts.

The use of said emission signal Dr allows the laser light having an emission mode based on the emission signal Dr to be acquired from the laser emitting element 26.

When this laser light is irradiated from the laser light irradiation piece 10 over the measurement zone 18, the scattered light is acquired from the particles in the water to be treated 8 that remain in the zone of Measurement 18. This scattered light is received by the part 12 that receives the scattered light.

Through photoelectric conversion of photoelectric conversion circuit 38, filter processing, and amplification, a light receiving signal Eo is obtained on the output side of amplifier 46, as shown in D of Figure 3. This light reception signal Eo flashes by means of the timing signal Ts, has a frequency of the modulation signal Ms and has an amplitude of a level that depends on the intensity of the scattered light.

When this light reception signal Eo is detected by the detector circuit 40, the output signal Do that flashes is acquired by means of the timing signal Ts and which has a DC level according to the intensity of the scattered light, as shown in E of figure 3. In the signal processing of this light receiving signal Eo, the output signal Do is acquired for example by half-wave rectification and detection of the output of the filter of bandpass 44 and subsequently holding the lower peak of the detection output.

Therefore, the lower value detection circuit 48 detects the measurement values already described d11, d12, d13 ..., d21, d22, d23 ... from the output signal Do through the A / D conversion.

<Measurement value calculation processing>

The lowest value detection circuit 48 executes the recording of a plurality of measurement values d for each set, the classification of a plurality of measurement values d extracted for each set, the extraction of the measurement values d and the calculation of the average of the measurement value.

(1) Storage (recording) of measurement value d

A of FIG. 4 is an example of the measurement value table 64. The measurement value table 64 is inserted into the data recording piece 58. In this embodiment, the measurement value table 64 stores, by way of example, a set table 64-1 that corresponds to the SI set and a set table 64 2 that corresponds to the SII set. Each of the assembly tables 64-1 and 64-2 stores the identification numbers No and the values of measurement d in the order of measurement on an assembly-by-assembly basis. The identification numbers do not indicate the order of measurement of the measurement values d and the specific information of the measurement values d. Each value of measurement d indicates a value of measurement d of F of FIG. 3. In this embodiment, two sets of values of measurement d are captured and stored, each set consisting of eight values of measurement d.

(2) Classification of measurement values d

Measurement values d are reordered in ascending order by sort processing. This classification uses a classification table 66.

B of Fig. 4 is an example of classification table 66. This classification table 66 is inserted into data recording piece 58. Classification table 66 stores, by way of example, a classification table 66-1 that corresponds to the SI set and a 66-2 classification table that corresponds to the SII set.

The classification processing is executed by processor 52 for each of the SI and SII sets. This embodiment shows the case where d16 <d12 ... d13 for values of the measurement values d11, d12 ... d18 of the SI set, and d23 <d28 ... d22 for values of the values of measurement d21, d22 ... d28 of the SII set. In this case, the measurement values d16, d12, d17 ... d13 are ordered in the classification table 66-1 in ascending order from bottom to top, as shown in B of figure 4. The values of the Measurements d23, d28, d24 ... d22 are sorted in leaderboard 66-2 in ascending order from bottom to top.

(3) First extraction of the measurement value d

In the first extraction, the lowest to the lowest multiple is extracted, for example, the second lowest measurement values d are extracted in ascending order from a plurality of measurement values d captured for each set.

A first measurement value extraction table 68 is used for the extraction of measurement values d. As shown in C of Figure 4, the measurement value extraction table 68 stores the measurement values d12 and d16 of the lower values extracted from the SI set and the measurement values d23 and d28 of the lower values extracted from the SII set.

(4) Second extraction of the measurement value d

In the second extraction, the lowest measurement value d is removed from the first extraction table of measurement values 68 used in the first extraction, and the measurement values d, to find an average value, are stored in an extraction table of measurement values 70.

This processing uses the measurement value extraction table 70. This measurement value extraction table 70 stores a plurality of measurement values d with the lowest measurement value d removed from the extraction table. of the measurement values 68. Since the correlation of the magnitude of the measurement values is, for example, d16 <d23 <d 12 <d28 in this embodiment, the measurement value d16 is removed . In this case, the measurement value extraction table 68 can be used as the measurement value extraction table 70.

(5) Calculation of the average measurement value dav

In calculating an average measurement value dav, a plurality of measurement values d are used to determine an average value. A plurality of measurement values d with the lowest measurement value d removed are used to determine the average value. In this embodiment, the three measurement values d23, d12 and d28 of the lower values are used to divide the plurality of measurement values d by a number Nt of measurement values. For example, the average measurement value dav is obtained by averaging {(d23 d12 d28) / 3}. The method of calculating the average measurement value dav may be a different calculation procedure than the average.

<Coagulation monitoring process>

Figure 5 shows an example of a coagulation monitoring process. The process is an example of a coagulation monitoring procedure of the present invention. The process is executed by computer processing (information processing) including the processor 52 and the memory piece 54 included in the lower value detection circuit 48.

In this process, adjustment of the coagulation monitoring condition is performed in a condition adjustment step (S1). This condition adjustment includes, for example, adjusting a number SN of sets to capture the measurement values d and a number of measurement values of each set. In this embodiment, two sets of measurement values d, each set consisting of eight values of measurement d, are stored by way of example to find an average measurement value.

After adjustment of the condition, it is determined whether a coagulation monitoring should be started (S2). If monitoring is started (YES on S2), the process goes to a laser emitting stage to activate the laser emitting element 26 (S3), changing to a laser light irradiation stage (S4). In the laser light irradiation step, the laser light is irradiated in the measurement area 18 as already described.

In a scattered light reception stage (S5), as already described, the scattered light is received from the measurement area 18, for conversion into a light reception signal having a level indicative of the scattered light intensity.

In a signal processing step (S6), as already described, the measurement values d are captured in sequence, from an output signal Do emitted from the detector circuit 40, within the circuit lower value detection 48.

In this case, a set of eight values of the measurement d is captured for example according to the established conditions (S7). It is determined whether the number of captured measurement values d has reached a predetermined number (S8). In this embodiment it is if a set of eight measurement values d have been reached.

If the number of measurement values has not reached the previously determined number (NO of S8), the acquisition of measurement values d continues. If this number of measurement values has reached the previously determined number (YES of S8), it is determined if the number of sets has reached a previously determined number (S9). If the number of sets has not reached the previously determined number (NO of S9), the capture of the measurement values d continues until the number of sets reaches the previously determined number. In this embodiment, two sets of measurement d values, each set consisting of eight measurement d values, are stored in the measurement value table 64.

If the predetermined number of sets has been reached (YES of S9), the measurement value d of each set is classified as already described (S10). In this classification, the values of measurement d are rearranged in ascending order for each set and stored in classification table 66.

On the ensemble basis, a plurality of measurement values of the lowest values are extracted from the measurement values d and stored (S11). In this embodiment, as already described, the two lowest measurement values d for each set are extracted and stored in the first measurement value extraction table 68.

The measurement value extraction table 70 stores a plurality of measurement values d stored in the measurement value extraction table 68 with the lowest measurement value d removed therefrom (S12).

The plurality of measurement values d is then averaged with the lowest measurement value d removed to determine an average measurement value dav (S13).

<Functions and effects of the first embodiment>

According to the first embodiment, the following functions and effects can be obtained.

(1) Since the lower value detection circuit 48 includes the processor 52 which is an example of a computation circuit and the data recording part 58 of the memory part 54 which is an example of a recording part recording the result of the calculation, the average measurement value dav in the form of the lowest value indicative of the coagulation state can be obtained through high speed processing by digital processing.

(2) In the computation process of the processor 52, the measurement values d that reach or exceed a certain number of times are captured at specific intervals so that the measurement values d from a value less than a nth value less among a plurality of measurement values d are stored in the data recording part 58 of the memory part 54. Then again, in the same way, the measurement values d are sampled to be retained in the recording part data 58 of memory piece 54. This calculation process is repeated a pre-specified number of times (twice or more), and thereafter a plurality of measurement values d stored in memory piece 54 are classified (rearrange) in ascending order from a low value, to extract the measurement values d from any value less than a previously specified lower m-value so that the plurality of values of the m Edition d are averaged to compute an average measurement value dav. That is, this average measurement value dav is an average value of the lowest value.

(3) In order to achieve a life-prolonging effect by shortening the emission time, the laser emitting element 26 emits light, for example during an emission time t = 0.2 [sec] at certain time intervals T = 2 [sec], to obtain the laser light. As already described, in the high flocculation density coagulation treatment with a high dosage of coagulant, the SS turbidity between flocs can only be measured several times or less per minute. If flocs are present in front of the scattered light receiving part 12, these flocs can protect the weak scattered light to be measured, until inhibiting the reception of the scattered light. When such a situation occurs frequently, it is anticipated to measure a value lower than the intensity of the actual scattered light. As in the previous embodiment, the light emission during an emission time t = 0.2 [sec] at certain time intervals T = 2 [sec], allows 30 measurements per minute so that a disadvantage of this type it can be avoided by making stable measurements of the turbidity ^s S in the shortest possible time.

(4) In the above embodiment, at a measurement frequency using laser light of an emission time of 0.2 [sec] at certain time intervals T = 2 [sec], the lowest values of for example two sets of measurement values d, each set consisting of eight values of measurement d, are sampled to collect the measurement values d of the lowest value and a second lowest value from a plurality of measurement values d of each set. This allows a lower value measurement value d to be removed from the two sets, four measurement values d, to obtain an average measurement value that is an average value of the remaining three measurement values. d. This attenuates the influence of the flocs, which is expected to occur at a high frequency, on the light scattered from uncoagulated colloidal particles, so that the influence of light protection due to the flocs can be eliminated. It is possible to avoid the interference of the flocs in the reception of the weak scattered light and to capture the treatment situation in real time with the increase of the measurement timings to improve the precision of the measurement. As a result, the state of the treatment of the water to be treated 8 can be measured stably to improve the measurement accuracy.

(5) In the above embodiment, by way of example, 16 measurement values are obtained for 36 [sec] if two sets of measurement values are used, each set consisting of 8 measurement values, for a light emission and reception of 0.2 [sec] at intervals of 2 [sec]. The lowest 4 measurement values, 2 by 1 set, are extracted from these measurement values so that 3 measurement values are averaged, except the lowest value. This makes it possible to avoid the influence of the flocs with measurement times increased per minute. Since the measurement values are averaged, except for the minimum measurement value, the influence of scattered light blocking and interference with the reception of weak scattered light by the flocs can be avoided so that the previous problems. It then becomes possible increase measurement timings, capture the treatment situation in real time and improve measurement accuracy.

(6) In the above embodiment, by way of example, two sets of measurement values are used, each set consisting of 8 measurement values, so that two measurement values are extracted from that of one value lowest and one second lower value from each set, with a measurement value d of the lower value being excluded from a total of 4 measurement values. The sampling number, such as the number of measurement values per set and the number of sets, could be changed without affecting the coagulation monitoring process. Rather, it could be adjusted according to the nature and type of water to be treated, 8 such as drainage, and the desired sampling conditions can be established.

(7) The laser emitting element 26 is activated by the emission signal Dr obtained by subjecting the timing signal Ts to amplitude modulation by the modulation signal Ms, the laser light thus obtained is irradiated on the measurement area 18, scattered light obtained from this measurement zone 18 is received and the lowest values of a plurality of measurement values obtained by the level of the light receiving signal are averaged to obtain an average measurement value indicative of the state of the coagulation treatment.

With reference to such a measurement and calculation process, the measurement of the intensity of the average scattered light cannot distinguish the scattered light from the coagulated substances in the water to be treated 8 from the light scattered from non-coagulated substances, which makes it difficult to capture the state of SS only, that is, non-coagulated substances. Typically, the intensity of the scattered light is proportional to the number of particles in the water to be treated 8 and is proportional to the fourth to sixth power of the radius of the particle. When SS coagulation continues, the number of particles in the water to be treated 8 decreases, with the result that the intensity of the scattered light decreases. As the radius of the particles of the coagulated substance becomes larger, the intensity of the light scattered per particle increases. For this reason, the measurement of the average intensity of the scattered light cannot capture the coagulation state properly, since both the scattered light from the coagulated substances and the scattered light from the non-coagulated substances are contained.

Although the detector circuit 40 detects a change in the intensity of the scattered light in the scattered light measurement, the light receiving signal processing and the measurement value calculation processing of the above embodiment, electrical signals are subjected to AM detection at a predetermined frequency in an earlier stage of detector circuit 40 to extract signal components from the scattered light. When a signal is detected, the detector circuit 40 undergoes a peak variation, the signal is input into the lower value detection circuit 48 for A / D conversion, and the signal strength of the lower value is considered as the intensity of the scattered light that has been scattered from the uncoagulated suspended solids in the water to be treated 8, detecting them distinguishable from the light scattered from the coagulated substances in the water to be treated 8 That is, a change in the lowest value of the signal intensity obtained from the scattered light is detected as a change in the number of uncoagulated colloidal particles in the water to be treated 8.

By making further reference to signal processing in this lowest value detection circuit 48, the signal strength of the lowest value is detected from the output signal Do. To detect this lower value, a low-amplitude portion of the waveform shown in D of Figure 3 is measured. Parts other than the low-amplitude portion indicate the case where coagulated colloidal particles and colloids Non-coagulated fines remain in measurement zone 18, while the low amplitude portion indicates the case where coagulated colloidal particles have passed from measurement zone 18 to other zones. Accordingly, since the lowest value detection circuit 48 detects the lowest value of the signal intensity, it becomes possible to measure the intensity of the scattered light in the case where only fine colloidal particles exist ( uncoagulated colloidal particles) in measurement zone 18, i.e. the number of fine colloidal particles. In this case, a decrease in the lowest value of the measurement values means a reduction of fine colloidal particles in the measurement zone 18, while an increase thereof means an increase in fine colloidal particles.

Among the measurement values d exemplified in Figure 3, the measurement values d11, d13, d22, and d23 not shown are values that contain coagulated colloidal particles, while the measurement values d12, d14, and d21 are values that they contain non-coagulated colloidal particles. Therefore, it will be understood that the measurement of the intensity of the scattered light, that is, the number of fine colloidal particles in the case in which only the fine colloidal particles (non-coagulated colloidal particles) are present in measurement area 18.

Therefore, since the lower value detection circuit 48 determines an average measurement value dav from a plurality of measurement values d11, d13, d22 and d23 excluding a lower measurement value d16, The influence of coagulated colloidal particles can be eliminated so that the turbidity of fine non-coagulated colloidal particles can be measured.

[Second embodiment]

Figure 6 shows a coagulation system according to a second embodiment. Coagulation system 72 is an example of a coagulation treatment system using coagulation monitoring device 2 according to the first embodiment. In Figure 6, the same parts as those in Fig. 1 are designated by the same reference numbers and will not be described again.

In the coagulation monitoring device 2, an average measurement value dav indicative of a turbidity SS of the water to be treated 8 is determined during the coagulation treatment in the coagulation reservoir 6 and is provided to a piece of control 74. This average dav measurement value indicates a value obtained from the treatment status of the water to be treated 8 under coagulation treatment within coagulation reservoir 6.

The control part 74 controls the coagulation treatment of the water to be treated 8 in the coagulation tank 6, such as the dosage of coagulant and the control of agitation. The coagulant is metered from a metering piece 76 into the water to be treated 8 in the coagulation reservoir 6. An agitator 78 arranged in the coagulation reservoir 6 is actuated by a drive part 80, the actuation of which is controlled by control piece 74.

Control piece 74 is composed, for example, of a computer, in which the coagulant dose is determined using the average measurement value dav provided from the coagulation monitoring device 2.

Figure 7 shows a dosage table of coagulant 82 for use in dosage selection. The coagulant dosage table 82 stores the coagulant dosage Y which is one of the coagulation conditions corresponding to the average measurement value dav. Using the coagulant dosage table 82, when determining an average dav measurement value, the Y dose corresponding to the average dav measurement value can be selected.

<Coagulation treatment of the coagulation system>

Figure 8 shows an example of a coagulation treatment process. In this process, it is determined whether a coagulation treatment is started (S11), and the coagulation treatment is started according to the result of the determination. When the coagulation treatment begins (YES of S11), the coagulation monitoring of the treatment state of the water to be treated in the coagulation tank 6 (S12) is carried out. This coagulation monitoring is carried out by the coagulation monitoring device 2. Details of the content of this treatment will not be described. The coagulation monitoring device 2 determines an average measurement value dav indicative of the treatment status of the water to be treated 8 (S13), for provision to the control part 74 of the coagulation system 72.

When the provision of the average measurement value dav is received, the control piece 74 selects a coagulant dosage as one of the coagulation conditions from the coagulant dosage table 82 (S14). As a result, the coagulant is metered from metering piece 76 (S15).

It is monitored if the coagulation treatment is finished (S16) and, if the coagulation treatment is not finished (NO from S16), the process returns to S12 to carry out a continuous coagulation treatment through the treatment from S12 to S16 .

If the coagulation treatment ends (YES on S16), the coagulation supervision ends (S17), to finish the coagulation treatment.

<Functions and effects of the second embodiment>

According to the second embodiment, the following functions and effects can be obtained.

(1) Stable dosing control is implemented due to real-time uptake of the coagulation treatment status and adoption of dosing control of the mean dav measurement value derived from the scattered light measurement value from which the influence of the flocs is eliminated or attenuated.

(2) The coagulation conditions of the water to be treated and the dosage of the coagulant can be found. (3) Coagulation performance can be improved by optimizing the dosage for the water to be treated and by running a stable coagulation treatment.

(4) It is possible to maintain the compensation capabilities of the coagulation system based on the measurement of the treatment status of the coagulation reservoir 6, while avoiding the excessive administration of coagulant to avoid the influence on environmental loads, due to which can implement a highly reliable coagulation treatment. This allows the necessary compensation capabilities to be maintained, for example for the PID control already described, if applicable, while maintaining the reliability of the treatment.

(5) Even in the case of water to be treated whose drainage species are frequently changed, such as drainage from a food manufacturing plant, appropriate coagulation treatment corresponding to the drainage species can be performed so that influences on environmental loads are avoided.

[Other embodiments]

(1) Although the above embodiment uses laser light that is emitted at predetermined time intervals and is amplitude modulated at a predetermined frequency, laser light subjected to amplitude modulation at a predetermined frequency can be used if priority is given to turbidity measurement without considering the life of the laser emitting element. In this case, a plurality of lower level signals can be extracted from continuous light reception signals at a predetermined timing.

(2) In the above embodiment, the bandpass filter 44 and amplifier 46 can be implanted by digital process.

(3) Although in the above embodiment, purified water, industrial water, drainage, etc. are exemplified as water to be treated 8 whose treatment status is monitored by coagulation monitoring device 2, this Water to be treated 8 can be a liquid to drink, such as fruit juice.

As set forth herein above, a description has been provided of the most preferred embodiment, etc., of the coagulation monitoring device, coagulation monitoring method, and coagulation system of the present invention. The present invention is not limited to the above descriptions. Naturally, various modifications and alterations could be made by those skilled in the art, based on the essence of the present invention that is defined in the claims or that is disclosed in the way of carrying out the invention. Obviously, such modifications and alterations are within the scope of the present invention.

INDUSTRIAL APPLICABILITY

According to the present invention, the treatment state of the coagulation treatment of the water to be treated, such as purified water, industrial water and drainage, can be captured in a stable and correct way, contributing to an efficient coagulation treatment.

EXPLANATIONS OF LETTERS OR NUMBERS

2 coagulation monitoring device

4 piece sensor

6 coagulation reservoir

8 water to be treated

10 piece irradiation laser light

12 piece scattered light receiving

14-1 first fiber optic

14-2 second fiber optic

16 protection element

18 measurement zone

20 piece light emitting laser

22-1 first support piece

-2 second support piece

corner piece at the vertex

laser emitting element

light emitting circuit

AM modulator circuit

timer circuit

Function generator

signal processing piece

photoelectric conversion circuit

detector circuit

photo detector

band pass filter

amplifier

lowest value detection circuit

A / D

processor

memory piece

program storage piece

data recording piece

RAM

display piece

, 64-1, 64-2 table of measurement values

, 66-1, 66-2 leaderboard

extraction table of the first measurement value

extraction table of the second measurement value coagulation system table

control piece

dosing piece

stirring piece

driving part

Claims (4)

RE IV IN D IC AC IO NES 1. A coagulation monitoring device (2) for monitoring a treatment status of the water to be treated (8) undergoing a coagulation treatment, comprising: a laser light irradiation part (10) configured to irradiate laser light in a measurement zone (18) of the water to be treated, such that the laser light is emitted at least at predetermined time intervals and subjected to an amplitude modulation at a previously determined frequency; a scattered light receiving part (12) configured to receive scattered light from particles of the water to be treated that are in the measurement zone; a signal processing part (36) configured to extract a measurement value indicative of a scattered light intensity, from the light receiving signal obtained at the scattered light receiving part; and a measurement value computation piece configured to continuously or discontinuously capture m plural measurement value sets, each set consisting of n measurement values where m = 2 or more and n = 2 or more; characterized in that the measurement value calculation piece is configured to extract a plurality of measurement values in ascending order from a lower value for each set, the measurement value calculation piece is configured to determine an average measurement value from a plurality of extracted measurement values with the lowest value removed therefrom. The coagulation monitoring device according to claim 1, further comprising: a laser light emitting part (20) configured to emit the laser light, the laser light emitting part comprising a laser emitting element, the element laser emitter being configured to emit light in response to an emission signal obtained by subjecting an intermittent timing signal at predetermined time intervals to an amplitude modulation performed by a modulation signal having an amplitude varying at a previously frequency determined. 3. A coagulation monitoring procedure that monitors a treatment status of the water to be treated (8) undergoing a coagulation treatment, the method comprising: a stage of irradiation with laser light (S4) consisting of irradiating laser light in a measurement zone (18) of the water to be treated, the laser light being emitted at least predetermined time intervals and subjected to a amplitude modulation at a predetermined frequency; a scattered light receiving step (S5) consisting of receiving the scattered light from particles of the water to be treated that are in the measurement zone; a signal processing step consisting of extracting a measurement value indicative of a scattered light intensity, from the light receiving signal obtained in the scattered light receiving step; and a measurement value calculation step that continuously or discontinuously captures m sets of plural measurement values, each set consisting of n measurement values, where m = 2 or more and n = 2 or more characterized in that the measurement value calculation step extracts a plurality of measurement values in ascending order from a lower value for each set, the measurement value calculation step determines an average measurement value from measurement values extracted with a lower value removed from them. 4. A coagulation system that performs a coagulation treatment of the water to be treated, comprising: a coagulation reservoir to cause the water to be treated to undergo a coagulation treatment; a coagulation monitoring device according to either of claims 1 and 2, configured to monitor the status of the treatment of the water to be treated in the coagulation tank; and a dosing means configured to dose a coagulant into the water to be treated in a dosage depending on the state of the treatment.